1. Field of the Invention
This invention relates to a liquid crystal display apparatus which is incorporated in a personal computer, a word processor, a television set, a viewfinder of a video camera and so forth for displaying an image thereon, and more particularly to a protective structure for a liquid crystal panel constituting a display apparatus.
2. Description of the Prior Art
General structure of a liquid crystal panel is shown in FIG. 5. Referring to FIG. 5, the liquid crystal panel includes a pair of substrates 1 and 2 disposed in an opposing relationship to each other with a predetermined gap left therebetween, and a liquid crystal layer 3 enclosed in the gap. The substrates 1 and 2 are adhered to each other by means of a sealer 4. A plurality of transparent electrodes 5 made of ITO or a like material are formed by patterning on the inner surfaces of the substrates 1 and 2. The optical characteristic of the liquid crystal layer 3 is varied by applying a driving voltage between opposing ones of the electrodes 5. A polarizing plate 6 is adhered to an outer surface of each of the substrates 1 and 2 and extracts an optical variation of the liquid crystal layer 3 as a variation in the transmission factor to effect display of an image.
Since a liquid crystal panel functions as a light valve, the substrates thereof are each formed from a transparent material such as a glass plate. A liquid crystal panel is generally produced by a cell dividing method. A large number of sealer partitions are first printed on one of the surfaces of a large glass plate, and another glass plate is adhered to the first glass plate to form liquid crystal cells. Then, scribe lines are drawn along the partitions, and the glass plates are broken to separate the liquid crystal cells from one another. Since the scribe break is employed, the dimensions of the outer profile of a liquid crystal cell or a liquid crystal panel are not always high in accuracy. Further, the glass substrates themselves of a liquid crystal panel are liable to break.
A polarizing plate which is employed in a liquid crystal panel normally has such a structure that a polyvinyl alcohol film, to which drawing processing has been applied, is held between a pair of cellulose acetate films or the like. Since such high molecular films are employed, the polarizing plate is liable to undergo a damage or the like.
Conventionally, a liquid crystal panel is handled in a condition wherein the end faces of the glass substrates and the surfaces of the polarizing plates are left exposed outside. For example, a liquid crystal panel is transported or conveyed while it is accommodated directly in a case. Consequently, there is a problem that an external force is applied directly to an end face of a glass substrate to provide a damage such as chipping to the end face of the glass substrate. There is another problem that the surface of a polarizing plate is damaged similarly.
Various problems are involved also in incorporation of a liquid crystal panel. A conventional incorporation structure of a liquid crystal panel is shown in FIG. 6. Referring to FIG. 6, an upper frame 8 is placed on a lower frame 7 with a recessed portion 9 formed therebetween to make up a housing for accommodating a liquid crystal panel 10 therein. However, if the liquid crystal panel 10 is accommodated directly in the recessed portion 9, then there is the possibility that a glass plate thereof may be damaged. Therefore, it has been the practice that the liquid crystal panel 10 is incorporated with a pair of resilient spacers 11 interposed between the liquid crystal panel 10 and the lower and upper frames 7 and 8. Further, in order to protect the surface of the polarizing plates 6 from a damage or the like, a retaining spacer 12 which involves a clearance or escape is disposed between the lower and upper frames 7 and 8. In this and also in the incorporation of a liquid crystal panel, there is a problem that a countermeasure for preventing a break of a glass substrate or a countermeasure for preventing a damage to a polarizing plate must necessarily be figured out, and accordingly, design is complicated.
Various problems are involved also in incorporation of a liquid crystal panel into an outer package. As shown in FIG. 7, a liquid crystal panel 10 is accommodated in a recessed portion 14 provided at a central portion of an outer package casing 13. Since the dimensions of the outer profile of liquid crystal panels have a dispersion as described above, trouble will sometimes occur when the liquid crystal panel 10 is to be accommodated into the recessed portion 14. Further, there is the possibility that a glass plate may be damaged or broken if an excessive pressure is applied to any of protrusions 15 which support the liquid crystal panel 10 from above and below. In order to prevent chipping, the protrusions 15 must necessarily be spaced as far as possible from the end faces of the glass plates, and relief portions 16 must be provided. Consequently, there is a problem that the structure is complicated.